1. Field of the Invention
Embodiments of the present invention generally relate to a method for mineral purification and more particularly to a method of removing metal sulfides from a molybdenite concentrate.
2. Description of the Related Art
Copper ore deposits containing copper sulfide minerals, such as chalcopyrite (CuFeS2), chalcocite (Cu2S), and bornite (Cu5FeS4) may contain minor amounts of molybdenite (MoS2). Recovery of the valuable molybdenite locked up in the ore is usually performed by a milling operation, followed by several flotation steps. The final molybdenite concentrate usually contains some sulfide minerals, and, to be commercial, the copper sulfide mineral content is typically reduced through a leaching step in which the copper sulfide minerals are dissolved by a leaching solution.
The leaching step is typically performed in a batch operation where the molybdenite concentrate is exposed to the leaching solution in a leaching vessel. After the leaching process, the leaching solution is separated from the molybdenite and is regenerated using chlorine gas. Due to the hazardous nature of the chlorine gas a batch operation with several safety procedures is required during the regenerating process, resulting in high labor, handling, and safety costs.
Accordingly, given the high costs associated with using chlorine gas, the batch operation using chlorine gas is suited to produce small amounts of material. For large amounts of products a continuous mode is normally more economical. In a continuous mode operation, leaching can be performed uninterrupted because the leaching solution is replenished as it is being used. Thus, in a continuous mode operation more molybdenite concentrate can be leached in the same amount of time it takes for leaching in a batch mode operation.
Therefore, a need exists for a method of regenerating a leaching solution for use in a leaching process that is more cost efficient, safer, and can be utilized in a continuous process as well as in a batch process.